/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.yushi.code.east.io;

import java.io.IOException;
import java.io.OutputStream;
import java.nio.channels.Channels;
import java.nio.channels.WritableByteChannel;

/**
 * Extended interface for a resource that supports writing to it. Provides an {@link
 * #getOutputStream() OutputStream accessor}.
 *
 * @author Juergen Hoeller
 * @since 3.1
 * @see OutputStream
 */
public interface WritableResource extends Resource {

  /**
   * Indicate whether the contents of this resource can be written via {@link #getOutputStream()}.
   *
   * <p>Will be {@code true} for typical resource descriptors; note that actual content writing may
   * still fail when attempted. However, a value of {@code false} is a definitive indication that
   * the resource content cannot be modified.
   *
   * @see #getOutputStream()
   * @see #isReadable()
   */
  default boolean isWritable() {
    return true;
  }

  /**
   * Return an {@link OutputStream} for the underlying resource, allowing to (over-)write its
   * content.
   *
   * @throws IOException if the stream could not be opened
   * @see #getInputStream()
   */
  OutputStream getOutputStream() throws IOException;

  /**
   * Return a {@link WritableByteChannel}.
   *
   * <p>It is expected that each call creates a <i>fresh</i> channel.
   *
   * <p>The default implementation returns {@link Channels#newChannel(OutputStream)} with the result
   * of {@link #getOutputStream()}.
   *
   * @return the byte channel for the underlying resource (must not be {@code null})
   * @throws java.io.FileNotFoundException if the underlying resource doesn't exist
   * @throws IOException if the content channel could not be opened
   * @since 5.0
   * @see #getOutputStream()
   */
  default WritableByteChannel writableChannel() throws IOException {
    return Channels.newChannel(getOutputStream());
  }
}
